1. Field of the Invention
The present invention relates to an image capturing apparatus and a control method for the image capturing apparatus, and more particularly, to an image capturing apparatus for carrying out autofocus control and a control method for the image capturing apparatus.
2. Description of the Related Art
For autofocus (AF) control of video cameras and the like, TV-AF type AF control is widely used in which an in-focus position is detected on the basis of the sharpness (contrast) of image signals generated with the use of an image sensor. Specifically, an AF evaluation value indicating the degree of contrast is generated for image signals captured sequentially while moving a focus lens, and the position of the focus lens at which the contrast reaches its maximum is searched as an in-focus position on the basis of the AF evaluation value.
However, in the case of shooting a person, focusing on the background rather than the person may occur due to the relationship in contrast between the person as a main object and the background.
In order to solve such a problem, image capturing apparatuses are known that detect a person and set a focus detection area for the purpose of focusing on the person. For example, image capturing apparatuses which have a face detection function and carry out focus detection for a focus detection area containing a face region (for example, Japanese Patent Laid-Open No. 2006-227080), and image capturing apparatuses which detect a person's eyes and carry out focus detection on the basis of the eyes (for example, Japanese Patent Laid-Open No. 2001-215403) are proposed.
However, in the focus detection using the conventional face detection function described above, in a case in which, for example, the person who is the object approaches suddenly and gets blurred, the amount of change in the AF evaluation value in the TV-AF type AF control is small, and it takes time to detect the direction in which the object is in focus (the in-focus direction). As a result, it takes time to focus, and thus there have been problems with AF tracking ability.